Do three of these high-energy workouts each week to blast fat, build endurance and maximize results.

 Ride a bicycle at a speed of at least 12 mph (one hour). Run a 12-minute mile for one hour or a 10-minute mile for 45 minutes. Play tennis (singles match, one hour; doubles, 75 minutes). Walk briskly at a 15-minute-mile pace for 90 minutes.  Swim laps at a moderate effort for 65 minutes.

4 Food Rules for More Energy

In addition to regular exercise, what you eat can make a big difference in helping you get through the day without a nap. Start with these simple rules.

1: Never Leave Home Without Your Water Bottle

"Hydration plays a major role in energy," notes Ashley Koff, R.D. That's especially true if you're breastfeeding, since nursing places even more demand on your fluid levels. Dehydration reduces blood volume, so less blood reaches your organs -- including your brain -- leaving you light-headed and dizzy. Drink water or seltzer, or shop the produce aisle. "Aim for at least 6 'hydration occasions' a day, which can include water-based vegetables," says Koff.

2: Don't Forget to Eat

With all the hullaballoo that comes with getting your little one fed, changed, and dressed, it's no wonder many moms grab a quick snack instead of a healthy meal. "Aim to eat a balanced meal or snack every three hours," says Koff. That means a mix of healthy carbs, protein and fat -- like whole-grain cereal with milk and chopped nuts, or plain Greek yogurt with berries and almonds -- to keep you satisfied.

3: Don't Use Coffee as a Crutch

Sure, you'll score a quick buzz from a double-shot latte, but prepare to bonk shortly thereafter. That's also true for energy drinks and sweets. "Energy fixes are often energy zappers in disguise," says Koff. "You'll spike, but then you'll be set up for a major crash."

4: Get the Right Mix of Nutrients

For a more natural, long-lasting boost, consume plenty of vitamins and minerals -- especially B vitamins (B6, B12 and folic acid, which help break food down into energy), and vitamin D, which plays a role in blood sugar regulation. Key foods include leafy vegetables, whole grains, eggs, grass-fed beef, shrimp, scallop and sardines.